This invention relates generally to orthotic appliances.
Fairly recently, greater attempts have been made to provide footwear which is anatomically correct so as to not only increase the comfort of the wearer, but also to minimize fatigue and injuries. This requires an analysis of the typical human gait. When one is moving substantially in a single linear direction, the gait consists of three distinct phases. First, the heel strike phase occurs during which the foot is essentially a "mobile adapter" ready to conform to the topographical contours encountered. Second, the transistion of mid-gait phase transforms the mobile adapter into a "rigid lever" where the mid-tarsal joint becomes locked preparing the foot for translation of the accumulated forces in a stable manner throughout the foot during the remainder of said cycle and the impact forces are dissipated through the ankle and leg bones to the upper torso. Third, the "toe roll" phase finishes the gait cycle and the next step is begun. The critical phase is the mid-gait or transition phase where the foot is transformed from a "mobile adapter" to a "rigid lever". The optimum configuration for the ankle at this point is to have the sub-talar joint in a neutral position as the mid-tarsal joint becomes locked and the foot becomes a "rigid lever". This allows the impact load to be properly dissipated. While podiatrists have long been aware of the need to maintain the foot's proper orientation relative to the leg to provide "rigid lever" and accordingly have prescribed orthoses for that purpose, the general populous rarely avails themselves of these services until after a certain amount of discomfort and/or damage has been done.
The following patents reflect the state of the art of which applicant is aware in so far as these patents appear to be germane to the patent process:
______________________________________ 2,669,814 Ritchey 1,240,066 French-Strasbach 2,680,919 Riggs 465,940 British-King 3,922,801 Zente ______________________________________
Of these, the patent to Ritchey appears to be of great interest since he teaches the use of an orthopedic device suitably positioned within a shoe or the like, in which the upper surface thereof has a complex contour addressed to the peculiarities of a given foot. The instant invention can be contrasted over this prior art by noting the contrasting ease with which the apparatus according to the instant application can be initially fitted to a person, or successively fitted as a function of time, while providing immediate relief.
Similarly, the patent to Riggs teaches the use of an insole type appliance having a compound contour like the Ritchey invention configured in such a manner as to provide foot relief based on Rigg's perception of a universal foot disorder.
Similarly, the Zente patent teaches the use of a liquid filled orthopedic apparatus comprised of a plurality of discrete internal liquid filled ampules which are strategically placed between upper and lower laminae and sealed in place to provide separate support for various parts of the foot.
The remaining references show the state of the art further, the British patent teaching the use of an insert having a compound contour based on the inventor's attempts at defining a single insert for addressing a wide spectrum of problems.